[IPV4]: Remove dead code from ip_output.c

skb_prev is assigned from skb, which cannot be NULL. This patch removes the
unnecessary NULL check.

Signed-off-by: Jayachandran C. <c.jayachandran at gmail.com>
Acked-by: James Morris <jmorris@namei.org>
Signed-off-by: Arnaldo Carvalho de Melo <acme@mandriva.com>
diff --git a/net/ipv4/ip_output.c b/net/ipv4/ip_output.c
index 1ad5202..87e3500 100644
--- a/net/ipv4/ip_output.c
+++ b/net/ipv4/ip_output.c
@@ -1023,10 +1023,7 @@
 			int alloclen;
 
 			skb_prev = skb;
-			if (skb_prev)
-				fraggap = skb_prev->len - maxfraglen;
-			else
-				fraggap = 0;
+			fraggap = skb_prev->len - maxfraglen;
 
 			alloclen = fragheaderlen + hh_len + fraggap + 15;
 			skb = sock_wmalloc(sk, alloclen, 1, sk->sk_allocation);